1. Field of the Invention
This invention relates to a method of producing rosemarinic acid or concentrate containing a high concentration of rosemarinic acid from germinated seeds of lamiaceous plants.
2. Description of the Prior Art
Rosemarinic acid is expected to be widely used as water-soluble strong antioxidant in the field of foods, as cosmetics and ultraviolet absorbent in the filed of cosmetics, and for pharmaceutical activity such as anti-inflammatory effect, antithrombotic effect and antiproliferative activity. It is known that lamiaceous, umbellifarous, and boroginaceous plants contain rosemarinic acid. Particularly lamiaceous plants contain a large amount of rosemarinic acid. Rosemarinic acid is mainly present as glucoside in leaves of lamiaceous plants although seeds thereof contain a small amount of rosemarinic acid.
With respect to the industrial production of rosemarinic acid, Japanese Unexamined Patent Publication-Nos. 7-187989A (1995) and 10-101572A (1998) disclose methods of extracting rosemarinic acid from a plant body such as leaves of perilla respectively. Furthermore, Japanese Unexamined Patent Publication No. 59-132894A (1984) and Japanese Examined Patent Publication No. 1-29558B (1989) disclose methods of cultivating tissue cells of lamiaceous plants respectively. However, since leaves of perilla can be obtained only in a specific season, rosemarinic acid cannot be produced throughout the year. Furthermore, the industrial production of rosemarinic acid requires a vast cultivation land and a cold storage so that perilla leaves are prevented from deterioration and decomposition for a long period. Thus, the industrial production of rosemarinic acid has a number of limitations. Additionally, it is difficult to control cultivation conditions in the tissue cultivation method, and the composition of product is unstable. Thus, basic problems remain unsolved in the industrial production of rosemarinic acid. A stable and efficient method of producing rosemarinic acid has not been established yet though usability of rosemarinic acid is well known.
Therefore, an object of the present invention is to provide a method of economically and efficiently producing rosemarinic acid or a concentrate containing a high concentration of rosemarinic acid.
To solve the aforesaid problems, the inventor examined variations of rosemarinic acid content in the seeds of lamiaceous plants during germination. The inventor found that an amount of rosemarinic acid contained in the seed of lamiaceous plants was obviously increased in a specific period of the germination although the seed originally contained only a small amount of rosemarinic acid. The present invention was made on the basis of this finding.
More specifically, an amount of rosemarinic acid contained in the seed does not shown a clear change in a period when the seed absorbs water and does not change its appearance. However, the amount of rosemarinic acid is rapidly increased at a stage where germination is observed and then it is gradually decreased after having reached its maximum. This property is common to seeds of lamiaceaous plants and is not lost after the seeds have been stored for a long period. Accordingly, it is possible to produce rosemarinic acid with a higher yield by using the germinated seed than by using non-germinated seed as starting material.
Furthermore, since the present invention is practiced inside a room, cultivation can be done in an industrial scale throughout the year even in a land unsuitable for raising the lamiaceous plants outdoors. Furthermore, since the seeds are germinated in a growing basket, a higher density of cultivation can be realized as compared with raising lamiaceous plants outdoors. Additionally, since a growth period is short, cultivation can be repeated at a number of times. Consequently, high productivity can be achieved even when growing or extracting facilities are small in scale and accordingly, the method of the invention can achieve larger economical improvement than the conventional raising outdoors.
Preferably, the lamiaceous plants are one or more plants belonging to subfamilies of Stachyoideae, Lavanduloideae, Ocimoideae, or Ajugoideae. Concrete examples include perilla frutescens BRITT. var. japonica HARA, perilla frutescens BRITT. var. acuta KUDO, and perilla frutescens BRITT. var. acuta KUDO forma vidis MAKINO. The seeds of lamiaceous plants germinate for 3 to 20 days or more preferably, for 5 to 8 days. Germinated seed is suitably dried and hull is removed from them. The germinated seed is fine ground into powder by a grinder. The powder can be used for various purposes as a composition containing rosemarinic acid. Further, an alcoholic extract from the powder can be served as a concentrate of rosemarinic acid. When the alcoholic extract is fractionated by water and water-insoluble organic solvent, a concentrate with a higher concentration can be obtained. Additionally, substantially pure rosemarinic acid can be obtained by column chromatography etc.
Other objects, features and advantages of the present invention will become clear upon reviewing the following description of the preferred embodiment.